Well tool device for opening and closing a fluid bore in a well

ABSTRACT

A well tool device includes a housing having an axial through bore. The well tool device further includes a sleeve section axially displaceable relative to the housing; a fluid flow preventing frangible disc; and an axial fluid passage bypassing the frangible disc when the well tool device is in an initial state, thereby allowing a fluid flow between a first location above the frangible disc and a second location below the frangible disc. The sleeve section includes an axial through bore aligned with the axial through bore of the housing. The axial fluid passage is closed when the well tool device is in a subsequent state. The fluid flow preventing frangible disc is provided in the bore of the sleeve section in sealing engagement with the sleeve section. The well tool device further includes a disc supporting device for supporting the frangible disc in relation to the sleeve section. The disc supporting device is releasably connected inside the sleeve section by means of a releasable connection device. The well tool device further includes a disintegration device disintegration of the frangible disc, wherein the well tool device is in a final state when the frangible disc has been disintegrated by the disintegration device.

FIELD OF THE INVENTION

The present invention relates to a well tool device for opening andclosing a fluid bore in a well. In particular, the present inventionrelates to a well tool device having a temporary open state, a temporaryclosed state and a permanent open state.

BACKGROUND OF THE INVENTION

In different types of well operations, it is a need for well tooldevices having a valve function, i.e. the well tool device needs to bereconfigured between an open state and a closed state.

Typically, the closed state is used for pressure testing purposes toensure that the well integrity is intact. The open state is typicallyduring production, to allow hydrocarbon fluids to be transported fromthe well to the topside of the well. During the installation of thecompletion string or tubing, it is preferred that the tubing is open, sowell fluid can flow into the tubing during the lowering of the tubinginto the well.

When the tubing is landed in the well head and the pressure controlequipment is installed above the tubing/well head, it is desired toreplace the heavy well fluid with a lighter completion fluid before theproduction packer is installed. In such a case, completion fluid ispumped down into the tubing and return fluid is received through theannulus. Again, during such operations, the tubing must be open.

In some operations, the open state is also used for pressure testingpurposes.

One such known well tool device is the Inter Remote Shutter Valve(IRSV), marketed by Interwell. The IRSV is initially closed and may beconnected to the lower part of the completion string. When thecompletion string is installed, the completion string above the IRSV maybe pressure tested to ensure that the production tubing is properlyinstalled. After testing, the IRSV is opened by crushing a glass discwithin the IRSV. When open, it is possible to test the production packeroutside of the completion string before production starts.

The IRSV may also be used in other well tools, such as plugs (forexample the Interwell ME plug, the Interwell HPHT plug etc).

The IRSV is described in the “Product Sheet: Inter Remote Shatter Valve(IRSV)” Rev. 4.0 dated 27 Sep. 2016.

U.S. Pat. No. 9,194,205, in the name of TCO AS, describes a device for asystem for conducting tests of a well, pipe or the like. In the device,a plug of a removable material is inserted in a pipe through a well tocarry out said tests. The device is characterized in that the wall partsof the pipe comprise channel borings that set up fluid connectionsbetween the well space and the well space above and below, respectively,the plug, and that it comprises a closing body that can close the fluidconnection permanently. The channel boring is preferably defined by anaxial hollow space/chamber in which a piston is arranged, said pistoncan be readjusted by an axial movement from a first position where thereis fluid connection through the channel and a second position where theconnection is permanently closed and cannot be reopened.

US 2011/0000663, in the name of TCO AS, describes a device for removalof a plug which is used in a well, a pipe, or the like for carrying outtests, and it is characterized by an element which, with an appliedforced, is arranged to penetrate into the plug material so that this iscrushed, said element is arranged to be supplied said force from anabove lying element. The element is preferably a ring the lower end ofwhich is arranged to be forced in a radial direction into the plugelement at axial driving of a hydraulic pressure piston. Furthermore,the element is integrated into the plug.

It is also known to use ball valves in the lower end of the completionstring, for testing of the production tubing and the production packer.However, if the ball valve fails, it is needed to mill out the ballvalve or to remove the completion string. None of these operations aredesired. Moreover, such valves often have a increased outer diameter ora reduced inner diameter. An increased outer diameter will make itdifficult to insert the completion string, while a reduced innerdiameter will reduce the flow rate capacity of the completion.

WO 2012066282 A2 discloses a valve assembly which is configured to becoupled to a tubing string. It comprises a housing defining a housingflow path for communicating with the tubing string, and a barrier memberlocated in the housing and configurable between a normally-closedposition in which the barrier member restricts access through thehousing flow path, and an open position in which access is permittedthrough the housing flow path. The valve assembly also comprises abypass arrangement reconfigurable between an open state in which thebypass arrangement defines a bypass flow path that communicates with thehousing flow path on opposite sides of the barrier member to permitfluid to bypass the barrier member and thereby fill the tubing string.One object of the present invention is to add functionality to the IRSVabove. One such added functionality is to provide the IRSV with aninitial open state. Hence, it is achieved that it is not necessary tofill fluid into the completion when adding new pipe sections to thecompletion string.

One object of the invention is to achieve a well tool device where theinner diameter is not substantially reduced or where the outer diameterof the device is not substantially increased. Accordingly, the object isthat the outer diameter of the well tool device is equal to orsubstantially equal to the outer diameter of the completion string thedevice is connected to, and that the inner diameter of the well tooldevice is equal to or substantially equal to the inner diameter of thecompletion string the device is connected to. In this case, the outerdiameter of the well tool device should be equal to or less than theouter diameter of for example the safety valve, which has an outerdiameter typically somewhat larger than the outer diameter of the tubingsegments.

To save time and resources, the completion string is run into thedrilling fluid. After the installation of the completion string, thedrilling fluid is circulated out and replaced by a completion fluidbefore the production packer is set. The object of the invention is toprovide a circulation valve with an initial open state, an intermediateclosed state and a final open state.

In some wells with a low reservoir pressure, a light weight fluid isoften circulated into the completion string before the well is openedfor production, as this light weight fluid will contribute to productionflowing out from the reservoir. Also in such a case it is preferred tohave an initial open completion string.

Another object of the invention is that it should be connectable to theupper part of the completion string, adjacent to, but below, the tubinghanger. Here, the well tool device serves the function of a second,upper barrier of the well, assuming that a first, lower barrier also ispresent in the well. The first barrier can be a prior art barrier, suchas a plug set in the completion string, or it may be another well tooldevice according to the present invention.

SUMMARY OF THE INVENTION

In the present description, the term “upper” and “lower” are used. Here,the part referred to as “upper” is relatively closer to the top of thewell than the part referred to as “lower”, i.e. the part referred to as“lower” is closer to the bottom of the well, irrespective of the wellbeing a horizontal well, a vertical well or an inclining well.

The present invention relates to a well tool device comprising a housinghaving an axial through bore, where the well tool device is comprising:

-   -   a sleeve section axially displaceable relative to the housing,        where the sleeve section comprises an axial through bore aligned        with the axial through bore of the housing;    -   a fluid flow preventing frangible disc;    -   an axial fluid passage bypassing the frangible disc when the        well tool device is in an initial state, thereby allowing a        fluid flow between a first location above the frangible disc and        a second location below the frangible disc;

where the axial fluid passage is closed when the well tool device is ina subsequent state;

where:

-   -   the fluid flow preventing frangible disc is provided in the bore        of the sleeve section in sealing engagement with the sleeve        section;    -   the well tool device further comprises a disc supporting device        for supporting the frangible disc in relation to the sleeve        section, where disc supporting device is releasably connected        inside the sleeve section by means of a releasable connection        device;    -   well tool device further comprises a disintegration device for        disintegration of the frangible disc, where the well tool device        is in a final state when the frangible disc has been        disintegrated by means of the disintegration device .

Hence, in the initial or first state, the fluid flow between the firstand second locations are allowed only via the axial fluid passage. Inthe intermediate or second state, fluid flow between the first andsecond locations are prevented. In the final or third state, thefrangible disc is broken, and fluid flow is allowed through the bores.In the final state, the axial fluid passage is still closed.

The disc supporting device is supporting the frangible disc in relationto the sleeve section until the disc supporting device released from thesleeve section. Preferably, the disc supporting device is connected tothe sleeve section in the initial state and in the intermediate state,while the disc supporting device is released from the sleeve section inthe final state.

In one aspect, the sleeve section is moved axially upwards in relationto the housing from the initial state to the intermediate state.Alternatively, the sleeve section is moved axially downwards in relationto the housing from the initial state to the intermediate state.

In one aspect, the well tool device comprises a sleeve locking systemfor preventing relative axial displacement between the housing and thesleeve section when the well tool device is in the intermediate state.

Hence, the well tool device cannot return from its intermediate state toits initial state again.

In one aspect, the sleeve locking system comprises:

-   -   a first recess provided in the bore of the housing;    -   a second recess provided in an outer surface of the sleeve        section, where the first and second recesses are axially aligned        in the intermediate state;    -   a pre-tensioned locking device provided in the first or second        recess, where the locking device is configured to lock the first        and second recesses to each other in the intermediate state.

The pre-tensioned locking device can be a pre-tensioned locking ring, aspring-biased locking pin, a ratchet ring, etc.

The pre-tensioned locking device can be a pre-compressed locking ring ora so-called snap ring, which in the initial state is provided in thesecond recess. When the recesses are aligned with each other in theintermediate state, the locking ring expands partially into the firstrecess and hence prevents relative axial movement between the housingand the sleeve section. Alternatively, the pre-tensioned locking deviceis a pre-expanded locking ring, which in the initial state is providedin the first recess. When the recesses are aligned with each other inthe intermediate state, the locking ring retracts partially into thesecond recess and hence prevents relative axial movement between thehousing and the sleeve section,

The well tool device may comprise an upper connection interface and/or alower connection interface for connection to a completion pipe,production tubing etc. In the initial state, fluids above and/or belowthe well tool device can be exchanged via the axial fluid passage. Inthe intermediate state, pressure testing can be performed. In the thirdstate, the well tool device allows full production through the bores.

In one aspect, the well tool device is comprising a first actuatingsystem for moving the sleeve section axially in relation to the housingfrom the initial state to the intermediate state.

In one embodiment, the axially displaceable sleeve section is releasablyconnected to the housing in the first state. This connection could beprovided by a shear pin etc., which are sheared off at a predeterminedload.

Alternatively, it is possible to move the sleeve section axially bymeans of controlling the fluid rate through the axial fluid passage. Ifan upwardly directed fluid flow rate is increased to a certain leveldetermined by the cross-sectional area of the passage, an increase inthe pressure below the frangible disc will occur. This increasedpressure could be used to move the sleeve section axially in relation tothe housing from the initial state to the intermediate state.

In one aspect, the first actuating system comprises:

-   -   a valve control system;    -   a valve controlled by the valve control system;    -   a first fluid line provided between the bore and the valve;    -   a piston axially displaceable within a piston cylinder;    -   a second fluid line provided between a first side of the piston        and the valve;

where a second side of the piston is connected to the sleeve section;

where the valve is preventing fluid flow between the bore and the firstside of the piston in the initial state;

where the valve is allowing fluid flow between the bore and the firstside of the piston in the intermediate state, thereby causing linearmovement of the piston within the piston cylinder and hence axialmovement of the sleeve section.

The second side of the piston can be connected to the sleeve section bymeans of a piston rod provided at least partially within the pistoncylinder. Alternatively, a further piston can be provided in the fluidcylinder or in fluid communication with the fluid cylinder, where thefurther piston is connected to the sleeve section. Here, the linearmovement of the piston will cause the linear movement of the furtherpiston and hence the sleeve section.

The fluid actuating system is preferably located in compartmentsprovided in the housing, i.e. radially between the bore and the outersurface of the housing.

The valve control system may comprise an electric actuator forcontrolling the valve. The electric actuator can control the valve toopen at a predetermined time by using a timer, at a signal detected by asensor, for example a signal in the form of hydraulic pulses detected bya pressure sensor, electromagnetic signals detected by an antenna etc.

In the initial state, the pressure within the fluid cylinder is lower orsubstantially lower than the expected well pressure in the well.Typically, the pressure within the fluid cylinder will have a so-calledatmospheric pressure in the initial state. This so-called atmosphericpressure is achieved by ensuring that the well tool device is in theinitial state, and then open and close a pressure-sealed entry into thefluid cylinder topside before the well operation starts, or duringmanufacturing. Hence, the so-called atmospheric pressure typicallycorresponds to the air pressure surrounding the well tool device at thetime when the fluid cylinder becomes closed. It should be noted that theatmospheric pressure typically varies dependent on the height above sealevel. When the well tool device is lowered into an oil and/or gas well,the fluid pressure in the well will be substantially higher than thepressure in the fluid cylinder, which will cause the piston to movelinearly inside the piston cylinder when the valve 52 is opened. Hence,variations in the so-called atmospheric pressure is neglectable withrespect to the fluid pressure in the well.

In one aspect, the housing comprises a first stop profile within thebore and the sleeve section comprises a second stop profile on its outersurface, where the second stop profile is engaged with the first stopprofile in the intermediate state.

In one aspect, the well tool device is comprising a second actuatingsystem for releasing the releasable connection device, thereby causing arelease of the disc supporting device from the sleeve section.

In one aspect, the disintegration device is fixed to the sleeve sectionwithin the bore of the sleeve section on the same side of the frangibledisc as the disc supporting device. When the releasable connectiondevice has been released by the second actuating system, relativemovement between the frangible disc and the sleeve section is possiblein one direction, as such movement is no longer prevented by the discsupporting device. Hence, the well tool device is configured to bebrought from the intermediate or second state to the final state bymeans of two steps:

First, the releasable connection device is actuated to release the discsupporting device.

Second, the frangible disc is configured to be pushed axially relativeto the sleeve section towards the disintegration device.

The second step can be performed by increasing the fluid pressure on oneside of the frangible disc. Preferably, the disintegration device andthe disc supporting device are located below the frangible disc. Hence,the frangible disc is pushed downwardly towards the disintegrationdevice by increasing the fluid pressure above the frangible disc.

In one aspect, the second actuating system comprises:

-   -   a valve control system;    -   a valve controlled by the valve control system;    -   a first fluid line provided between the bore and the valve;    -   a piston axially displaceable within a piston cylinder;    -   a second fluid line provided between a first side of the piston        and the valve;

where a second side of the piston is connected to the releasableconnection device;

where the valve is preventing fluid flow between the bore and the firstside of the piston in the initial state and intermediate state;

where the valve is allowing fluid flow between the bore and the firstside of the piston to initiate the final state, thereby causing linearmovement of the piston within the piston cylinder and hence release ofthe releasable connection device.

In one aspect, the second actuating system and the releasable connectiondevice are provided on opposite sides of the frangible disc.

In one aspect, a piston rod is in one end connected to the second sideof the piston, and is in a second end provided in contact with anactuating rod of the releasable connection device.

In one aspect, the actuating rod is provided in an axial bore providedin the sleeve section.

The second actuating system is similar to, or identical to, the firstactuating system. If both actuating systems are actuated by a number ofpressure cycles, the first actuating system must be designed to actuatethe valve after fewer pressure cycles than the second actuating system,to ensure correct operation of the tool.

DETAILED DESCRIPTION

Embodiments of the invention will now be described in detail, withreference to the enclosed drawings, where:

FIG. 1 illustrates a cross sectional view of the well tool device in aninitial state;

FIG. 2 illustrates a cross sectional view of the well tool device in anintermediate state;

FIG. 3 illustrates a cross sectional view of the well tool device in afirst phase of a final state;

FIG. 4 illustrates a cross sectional view of the well tool device in asecond phase of the final state;

FIG. 5 illustrates an enlarged view of FIG. 1;

FIG. 6 illustrates an enlarged view of FIG. 2;

FIG. 7 illustrates an enlarged view of FIG. 3.

It is now referred to FIGS. 1-4. In FIG. 1-4, the left side of thedrawings are facing towards the upper side of the well, while the rightside of the drawings are facing towards the lower side of the well. InFIG. 5-7, the upper side of the drawings are facing toward the upperside of the well, while the lower side of the drawings are facingtowards the lower side of the well.

A well tool device I is generally referred to with reference number 1.In FIG. 1 and 5, the well tool device 1 is in an initial state S1. InFIGS. 2 and 6, the well tool device 1 is in an intermediate state S2. InFIGS. 3 and 7, the well tool device 1 is in a first phase of a finalstate S3, while in FIG. 4, the well tool device 1 is in a second phaseof the final state S3. These states S1, S2 and S3 will be described indetail together with the well tool device 1 below.

The well tool device 1 comprises an outer housing 10 with an axialthrough bore 11. The well tool device 1 comprises an upper connectioninterface 13 a and a lower connection interface 13 b for connection to acompletion pipe, production tubing etc. These connection interfaces 13a, 13 b may be threaded connection interfaces, or other types ofconnection interfaces. The axial through bore 11 has a diameter D11which is typically equal to the inner diameter of the completion pipe,production tubing etc.

A longitudinal central axis II of the well tool device 1 is indicated inFIGS. 2. and 3.

One section 11 a of the axial through bore 11 has a larger diameter D11a than the diameter D11. This section 11 a forms a compartment for asleeve section 20. The sleeve section 20 is axially displaceablerelative to the housing 10. The sleeve section 20 comprises an axialthrough bore 21 aligned with the axial through bore 11 of the housing10. The axial displacement of the sleeve section 20 is limited by thelength of the section 11 a of the bore 11. In FIG. 1, it is shown thatthe housing 10 comprises a first stop profile 16 within the bore 11.This first stop profile 16 forms the border between the bore 11 and thebore 11 a. The sleeve section 20 comprises a second stop profile 26 onits outer surface, where the second stop profile 26 is engaged with thefirst stop profile 16 in the intermediate state S2.

In addition, the axial displacement of the sleeve section 20 is limitedby a sleeve locking system 4, which will be described more in detailbelow.

The axial through bore 21 has an inner diameter D21 which is equal tothe diameter D11 of the bore 11. Hence, the sleeve section 20 itselfdoes not limit fluid flow through the well tool device 1 substantially.

The well tool device 1 further comprises a fluid flow preventingfrangible disc 30 provided in the bore 21 in sealing engagement with thesleeve section 20. As is known from prior art, the frangible disc 30 istypically made of hardened glass, and is shaped as a cylinder withchamfered upper and lower edges. These chamfered upper and lower edgesare supported in a so-called seat in the sleeve section 20. In FIG. 5,it is shown that an o-ring 32 is provided radially between the frangibledisc 30 and the sleeve section 20. Hence, as long as the disc 30 ispresent in the sleeve section 20, axial fluid flow through the bore 21of the sleeve section 20 is prevented.

As shown in FIG. 5, o-rings 36 is also provided radially between thesleeve section 20 and the housing 10, i.e. radially outside of thesleeve section 20 and radially inside of the housing 10. These O-rings36 prevents axial fluid flow through the bore 11 and bore 11 a, on theoutside of the sleeve section 20. The o-rings 36 are axially displacedat a distance D36 above the o-ring 32 of the disc 30. In FIG. 6, it isshown that the O-ring 32 is axially (vertically in FIG. 5) aligned withthe o-rings 36.

The axially displaceable sleeve section 20 can be releasably connectedto the housing 10 in the first state S1. This connection could beprovided by a shear pin (not shown), which are sheared off at apredetermined load.

Devices 40, 41 and 42

In the present embodiment, the well tool device 1 comprises a discsupporting device 41 for supporting the frangible disc 30 in relation tothe sleeve section 20. The upper chamfered edge of the disc 30 and theside surface of the disc 30 are supported by the sleeve section 20,while the lower chamfered edge of the disc 30 is supported by the uppersupporting surface 41 a of the disc supporting device 41. Hence, whenthe disc supporting device 41 is removed, nothing prevents the disc 30from being pushed axially downwards in relation to the sleeve section20. When comparing FIGS. 6 and 7, it is shown that the disc supportingdevice 41 can be moved downwardly a distance D41 with respect to thesleeve section 20, corresponding to a distance between the lower end ofthe disc supporting device 41 and a stop 28 provided as part of thesleeve section 20.

The disc supporting device 41 is releasably connected inside the sleevesection 20 by means of a releasable connection device 42. The releasableconnection device 42 is a cycle actuated mechanism described in priorart EP297892613.

The well tool device 1 further comprises a disintegration device 40 fordisintegration of the frangible disc 30. The disintegration device 40 isfixed to the sleeve section 20, within the bore 21 and is located at ashort distance below the frangible disc 30. The disintegration device 40is provided at a distance below frangible disc 30 which is shorter thanthe distance D41. Hence, when the disc supporting device 41 is releasedfrom the sleeve section 20, the disc 30 may be pushed downwardly intocontact with the disintegration device 40, thereby causingdisintegration of the disc 30.

Axial Fluid Passage 2

In FIG. 1 and FIG. 4, it is shown that the well tool device 1 comprisesan axial fluid passage 2, allowing fluid to bypass the frangible disc30. This bypass fluid flow is indicated by arrow FF1 between a firstlocation L1 above the frangible disc 30 and a second location below thefrangible disc 30. It should be noted that FF1 is bi-directional, i.e.fluid may flow from the first to the second location and from the secondto the first location, dependent on the fluid pressure on the respectivesides of the disc 30.

In FIG. 5, it is shown that the axial fluid passage 2 comprises firstand second fluid lines 22 a, 22 b provided in a radial direction throughthe sleeve section 20, i.e. from the bore 21 on the inside of the sleevesection 20 to the bore 11 or 11 a of the housing 10 outside of thesleeve section 20. The first fluid line 22 a is located above the disc30, and the second fluid line 22 b is located below the disc 30. Inaddition, the axial fluid passage 2 comprises a third fluid line 12provided as an axial recess in the housing 10. The third fluid line 12provides fluid communication between the first and second fluid lines 22a, 22 b. Hence, as shown in FIG. 5, fluid is allowed to flow from thefirst location LI, through the first fluid line 22 a, through the thirdfluid line 12, through the second fluid line 22 b and then to the secondlocation L2. As mentioned above, fluid flow in the opposite direction isalso possible. From FIG. 5 it is apparent that the well tool device 1comprises several such axial fluid passages 2 spaced apart from eachother circumferentially around the sleeve section 20 and housing 10.

Hence, in the initial state S1 of FIGS. 1 and 5, the well tool device 1is said to be open, as fluid flow through the device I is allowed viathe axial fluid passage 2 bypassing the frangible disc 30.

First Actuating System 50 and Second Actuating System

The well tool device 1 comprises a first actuating system 50 and asecond actuating system 60, shown in FIG. 1. The first and secondactuating systems 50, 60 are provided in the housing 10, for examplewithin a compartment of the housing 10. The first actuating system 50 isprovided in the lower part of the housing 10, while the second actuatingsystem 60 is located in the upper part of the housing 10.

The first actuating system 50 comprises a valve control system 51 forcontrolling a valve 52. The first actuating system 50 further comprisesa piston 54 axially displaceable within a piston cylinder 55. A first,lower, side of the piston 54 is faced towards the valve 52, while asecond, upper, side of the piston 54 is faced towards the sleeve section20.

A first fluid line 53 a is provided between the bore 11 and the valve52. A second fluid line 53 b is provided between the valve 52 and thelower part of the piston 54. Hence, the first side of the piston 54 isprovided in fluid communication with the valve 52. The second side ofthe piston 54 is connected to the sleeve section 20 by means of a rod56.

The valve 54 can be controlled to be in two different positions, a firstposition in which the valve 54 is preventing fluid flow between thefirst and second fluid lines 53 a, 53 b and a second position in whichthe valve 54 is allowing fluid flow between the first and second fluidlines 53 a, 53 b.

The second actuating system 60 comprises a valve control system 61 forcontrolling a valve 62. The second actuating system 60 further comprisesa piston 64 axially displaceable within a piston cylinder 65. A first,upper, side of the piston 64 is faced towards the valve 62, while asecond, lower, side of the piston 64 is faced towards the sleeve section20.

A first fluid line 63 a is provided between the bore 11 and the valve62. A second fluid line 63 b is provided between the valve 62 and thelower part of the piston 64. Hence, the first side of the piston 64 isprovided in fluid communication with the valve 62. The second side ofthe piston 64 is connected to a piston rod 66. The piston rod 66 is usedto release the connection device 42. In FIG. 2, it is shown that thepiston rod 64 is provided in contact with an actuating rod 43 of thereleasable connection device 42. The actuating rod 43 is provided in acompartment within the sleeve section 20.

The valve 64 can be controlled to be in two different positions, a firstposition in which the valve 64 is preventing fluid flow between thefirst and second fluid lines 63 a, 63 b and a second position in whichthe valve 64 is allowing fluid flow between the first and second fluidlines 63 a, 63 b.

The valve control system 51 may comprise an electric actuator forcontrolling the valve 52. The electric actuator can control the valve 52to open at a predetermined time by using a timer, at a signal detectedby a sensor, for example a signal in the form of hydraulic pulsesdetected by a pressure sensor, electromagnetic signals detected by anantenna etc. In the present embodiment, pressure pulses are detected bythe valve control system 51 via openings 59 to the bore 11. In similarway, the valve control system 61 of the second actuating system 60detects pressure pulses via openings 69 to the bore 11.

It should be noted that the number of pulses needed for the valvecontrol system 51 to actuate the valve 52 is different than the numberof pulses needed to actuate the valve 62, as the first actuating system50 should be actuated before the second actuating system 60.

It should also be noted that the pressure within the fluid cylinders 55,65 on the second side of the pistons 54, 64, i.e. on the upper side ofpiston 54 and on the lower side of piston 64, is lower or substantiallylower than the expected well pressure in the well. Such a lower orsubstantially lower pressure can be a so-called atmospheric pressure asdiscussed in the introduction above.

The Sleeve Locking System 4

The sleeve locking system 4 mentioned above will now be described withreference to FIGS. 1 and 2. The sleeve locking system 4 comprises afirst recess 14 provided in the bore 11 of the housing 10, a secondrecess 24 provided in an outer surface of the sleeve section 20 and apre-tensioned locking device 34 provided in the first or second recess14, 24. In the present embodiment, the pre-tensioned locking device 34is a pre-compressed locking ring or a so-called snap ring, which in theinitial state S1 is provided in the second recess 24.

In FIG. 1, the first and second recesses 14, 24 are provided axiallydisplaced from each other. In FIG. 2, the first and second recesses 14,24 are axially aligned with each other. Here, the locking ring expandspartially into the first recess 14 and hence prevents relative axialmovement between the housing 10 and the sleeve section 20.

Operation of the Well Tool Device

The operation of the well tool device 1 will now be described.

In the initial state S1 of FIGS. 1 and 5, bidirectional fluid flow FF1is allowed through the device 1. In this state, fluids in the wellborecan be replaced.

When desired, the well tool device 1 can be actuated to its intermediatestate S2. In the present embodiment, this is done by changing thepressure in bore 11 in a predetermined pattern, such as by cycling thepressure a predetermined number of times. This will actuate the valvecontrol system 51 of the first actuating system 50, causing the valve 52to rotate and allowing the fluid in the bore 11 to enter the pistoncylinder 55 on the first side of the piston 54, which again will causethe piston 54 to push the sleeve section 20 upwardly by means of thepiston rod 56.

The sleeve section 20 will move upwardly until the second stop profile26 contacts or engages the first stop profile 16, as indicated by thedistance D36. When the sleeve section 20 is in this position, the firstand second recesses 14, 24 are axially aligned with each other, and thesleeve locking system 4 provides that the sleeve section 20 is axiallylocked to the housing 10. The well tool device 1 is now in theintermediate state. It should be noted that it is not possible to movethe sleeve section 20 downwardly again, as the sleeve locking system 4will prevent such movement.

As shown in FIGS. 2 and 6, the axial fluid passage 2 is now closed. Asdescribed above, the o-rings 32 and 36 are axially aligned. Now, theo-rings 36 are located between the first and third fluid lines 22 a, 22b.

In this intermediate state, the actuating rod 43 is moved together withthe sleeve section 20 to a position where the actuating rod 43 is incontact with the piston rod 66 of the second actuating system 60.

In this intermediate state, the completion string or tubing string abovethe well tool device can be pressure tested.

When desired, the well tool device 1 can be actuated to its final stateS3. In the present embodiment, this is done in two substeps. The firstsubstep is to change the pressure in bore 11 (above the disc 30) in apredetermined pattern, such as by cycling the pressure a predeterminednumber of times. This will actuate the valve control system 61 of thesecond actuating system 60, causing the valve 62 to rotate and allowingthe fluid in the bore 11 to enter the piston cylinder 65 on the firstside of the piston 64, which again will cause the piston 64 to push theactuating rod 43 downwardly by means of the piston rod 66

This will again release the releasable connection device 42, causingthat the disc supporting device 41 becomes released from the sleevesection 20.

The second substep is to increase the pressure above the disc 30, inorder to push the disc 30 downwardly towards the disintegration device40. As the disc supporting device 41 is released, the disc supportingdevice 41 will be pushed downwardly with the disc 30.

As the disc 30 comes into contact with the disintegration device 40, thedisc will disintegrate as shown in FIGS. 3 and 7 into small fragments,which will be transferred with the well flow.

In FIG. 4, the final state S3 is shown, where a second bidirectionalfluid flow FF2 is indicated. As described above, the inner diameter ofthe well tool device 1, indicated by diameters D11 and D21, can be equalto the inner diameter of the string being connected to the well tooldevice 1. Hence, the well tool device 1 does not represent a fluidrestriction in the string in the final state S3. In the third state S3,the well tool device 1 allows full production through the bores 11, 21.

In the description above, the sleeve section 20 is moved upwardly fromthe first state S1 to the intermediate and closed state S2. This is anadvantage, as in this closed state, the first stop profile 16 of thehousing in contact with the second stop profile 26 of the sleeve, whereit is relatively easy to dimension these profiles to withstand theexpected well pressure. If the sleeve section 20 was to move downwardlyfrom the initial to the closed state, the locking mechanism for lockingthe sleeve section in the closed state must be dimensioned and tested tohandle the expected well pressure—which may be difficult to obtain.

Another advantage is that if there is a failure in the first actuatingsystem 50, it will still be possible to close the well tool device 1.This can be performed by increasing the pressure in the entire well,i.e. increasing the pressure above and below the disc 30 (typicallyincreasing the pressure towards the production packer). Then, thepressure can be bled off from the top side, causing the pressure to behigher below the disc 30 than above the disc 30. This pressuredifference over the axial fluid passage 2 will then be so large that thesleeve section 20 will be pushed upwardly by means of the differentialpressure over the axial fluid passage 2.

Alternative Embodiments

It should be noted that in case the well tool device 1 is intended to beprovided in the bottom end of a completion pipe, the lower connectioninterface 13 b may be used for connection to a mule shoe or a wirelinere-entry guide.

The enlarged section 11 a of the bore 11 is not essential for thepresent invention. The axial displacement of the sleeve section 20 canbe limited by other types of stops causing an engagement between thesleeve section 20 and the housing 10. However, without the enlargedsection 11 a, it is assumed that the diameter D21 of the sleeve section20 would have to be substantially smaller than the diameter D11 of thebore 11.

The pistons 54, 64 are described above to be mechanically connected tothe sleeve section 20 and the actuating rod 43 respectively. It shouldbe noted that a further piston can be provided in the fluid cylinder orin fluid communication with the fluid cylinder, where the further pistonis connected to the sleeve section 20. In such a case, the pistons 54,64 can be considered to be hydraulically connected to the sleeve section20 and the actuating rod 43 respectively.

1. A well tool device comprising a housing having an axial through bore,wherein the well tool device further comprises: a sleeve section axiallydisplaceable relative to the housing, wherein the sleeve sectioncomprises an axial through bore aligned with the axial through bore ofthe housing; a fluid flow preventing frangible disc; and an axial fluidpassage bypassing the frangible disc when the well tool device is in aninitial state, thereby allowing a fluid flow between a first locationabove the frangible disc and a second location below the frangible disc;wherein the axial fluid passage is closed when the well tool device isin a subsequent state; wherein: the fluid flow preventing frangible discprovided in the bore of the sleeve section in sealing engagement withthe sleeve section; the well tool device further comprises a discsupporting device for supporting the frangible disc in relation to thesleeve section, wherein disc supporting device is releasably connectedinside the sleeve section by means of a releasable connection device;the well tool device further comprises a disintegration device fordisintegration of the frangible disc, wherein the well tool device is ina final state when the frangible disc has been disintegrated by means ofthe disintegration device.
 2. The well tool device according to claim 1,wherein the well tool device (1) comprises a sleeve locking system forpreventing relative axial displacement between the housing and thesleeve section when the well tool device is in the intermediate state.3. The well tool device according to claim 2, wherein the sleeve lockingsystem comprises: a first recess provided in the bore of the housing; asecond recess provided in an outer surface of the sleeve section,wherein the first and second recesses are axially aligned in theintermediate state; a pre-tensioned locking device provided in the firstor second recess, wherein the locking device is configured to lock thefirst and second recesses to each other in the intermediate state. 4.The well tool device according to claim 1, wherein the well tool deviceis comprising a first actuating system for moving the sleeve sectionaxially in relation to the housing from the initial state to theintermediate state.
 5. The well tool device according to claim 4,wherein the actuating system comprises: a valve control system; a valvecontrolled by the valve control system; a first fluid line providedbetween the bore and the valve; a piston axially displaceable within apiston cylinder; a second fluid line provided between a first side ofthe piston and the valve; wherein a second side of the piston isconnected to the sleeve section; where the valve is preventing fluidflow between the bore and the first side of the piston in the initialstate; wherein the valve is allowing fluid flow between the bore and thefirst side of the piston in the intermediate state, thereby causinglinear movement of the piston within the piston cylinder and hence axialmovement of the sleeve section.
 6. The well tool device according toclaim 1, wherein: the housing comprises a first stop profile within thebore; the sleeve section comprises a second stop profile on its outersurface; wherein the second stop profile is engaged with the first stopprofile in the intermediate state.
 7. The well tool device according toclaim 1, wherein the well tool device is comprising a second actuatingsystem for releasing the releasable connection device, thereby causing arelease of the disc supporting device from the sleeve section.
 8. Thewell tool device according to claim 7, wherein the second actuatingsystem comprises: a valve control system; a valve controlled by thevalve control system; a first fluid line provided between the bore andthe valve; a piston axially displaceable within a piston cylinder; asecond fluid line provided between a first side of the piston and thevalve; wherein a second side of the piston is connected to thereleasable connection device; wherein the valve is preventing fluid flowbetween the bore and the first side of the piston in the initial stateand intermediate state; wherein the valve is allowing fluid flow betweenthe bore and the first side of the piston to initiate the final state,thereby causing linear movement of the piston within the piston cylinderand hence release of the releasable connection device.
 9. The well tooldevice according to claim 8, wherein the second actuating system and thereleasable connection device are provided on opposite sides of thefrangible disc.
 10. The well tool device according to claim 8, wherein apiston rod (66) in one end is connected to the second side of thepiston, and in a second end is provided in contact with an actuating rodof the releasable connection device.
 11. Well tool device according toclaim 10, wherein the actuating rod is provided in an axial boreprovided in the sleeve section.
 12. The well tool device according toclaim 1, wherein the disintegration device is fixed to the sleevesection on the same side of the frangible disc as the disc supportingdevice.
 13. The well tool device according to claim 1, wherein thefrangible disc is configured to be pushed axially relative to the sleevesection towards the disintegration device after release of the discsupporting device.